(Taken From Official Guidebook)
Porta Nola and the City Walls
Porta Nola owes its name to the fact that it opened onto the road leading to the Nola countryside. An inscription in the Oscan language (no longer present) on the facade of the gate attributes its construction to the meddix tuticus (supreme funtionary) Vibio Popidio (approximately 3rd Cent. BC). It has surfaces of opua quadratum, consisting on rows of tufa blocks, and a barrel vault in opus caementicium. In the keystone of the internal arch is a sculpture of Minerva’s head, almost as though to place the entrance to the city under the goddess’s protection. The outer gate is preceded by two bastions fitted into the walls: these were intended to force any attackers to come out into the open in order to cross a dangerous gorge. The south section of the walls, to the right leaving the city, was rebuilt to approximately 100 m in opus caementicium, perhaps after 100 BC. The north section instead retains its dual structure, with limestone base and upper portion in tufa.